Reduced IMU power consumption in a wearable device

ABSTRACT

Systems and methods for detecting touch events with an accelerometer are disclosed. In one aspect, a method includes measuring first accelerometer data at a first rate, detecting a first touch event based on the first accelerometer data, in response to detecting the first touch event, measuring second accelerometer data at a second rate, determining whether a second touch event is detected based on the second accelerometer data, measuring third accelerometer data at the first rate in response to an absence of the second touch event being detecting in the second accelerometer data over a predetermined threshold period of time.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/738,497, filed on Jan. 9, 2020, which is a continuation of U.S.patent application Ser. No. 15/798,012, filed on Oct. 30, 2017, each ofwhich are hereby incorporated by reference herein in their entireties.

BACKGROUND

Wearable devices have several design constraints. One of theseconstraints is weight. Another is size. To reduce size and weight, awearable device may make use of a relatively small battery. As a result,power consumption of the wearable device can be an important factor inuser satisfaction. Therefore, reducing power consumption in wearabledevices continues to be an important design consideration.

BRIEF DESCRIPTION OF THE DRAWINGS

Various ones of the appended drawings merely illustrate exampleembodiments of the present disclosure and should not be considered aslimiting its scope.

FIG. 1 is a front perspective view of one embodiment of a camera device.

FIG. 2 is a block diagram illustrating a networked system includingdetails of a camera device, according to some example embodiments.

FIGS. 3 and 4 illustrate wearable devices including transmissioncomponents according to certain example embodiments.

FIG. 5 is a state transition diagram that may be implemented in at leastsome of the disclosed embodiments.

FIG. 6 is a block diagram of an example IMU 215, according to someexample embodiments.

FIG. 7 a data flow diagram of one exemplary method of training a modelto detect tap inputs based on acceleration data, according to someexample embodiments.

FIG. 8 is a flowchart of a method for managing a sampling rate of aninertial measurement unit, according to some example embodiments.

FIG. 9 is a block diagram illustrating an example of a softwarearchitecture that may be installed on a machine, according to someexample embodiments.

FIG. 10 illustrates a diagrammatic representation of a machine in theform of a computer system within which a set of instructions may beexecuted for causing the machine to perform any one or more of themethodologies discussed herein.

DETAILED DESCRIPTION

The description that follows includes systems, methods, techniques,instruction sequences, and computing machine program products thatembody illustrative embodiments of the disclosure. In the followingdescription, for the purposes of explanation, numerous specific detailsare set forth in order to provide an understanding of variousembodiments of the inventive subject matter. It will be evident,however, to those skilled in the art, that embodiments of the inventivesubject matter may be practiced without these specific details. Ingeneral, well-known instruction instances, protocols, structures, andtechniques are not necessarily shown in detail.

Disclosed are methods, systems, and devices for reducing powerconsumption in a wearable device. The wearable devices disclosed includean inertial measurement unit (IMU). The IMU may be used to detect motionin the wearable device. The motion detected by the IMU may be used forexample, to determine whether to maintain the device in an active stateor allow the device to enter a low power state.

In some aspects, the IMU may be controlled through at least threedifferent states. In a first state, the IMU is placed in a low powerstate. The low power state maintains an IMU sampling rate at a firstrate. This rate may be relatively low to reduce power consumption of theIMU. In this state, the IMU may be unable to determine direction of anymotion, but instead only detect that the motion is present. A second IMUstate may set a sampling rate of the IMU at a second rate. The secondrate is higher than the first rate. With this higher second samplingrate, the IMU is able to detect directional information relating tomotion. However, the second sampling rate may not support detection of a“double tap” input. For example, the speed of the “double tap” may betoo fast for both taps to be accurately detected with the secondsampling rate.

Upon detection of a first tap while in the second state, the IMU may bemoved to a third state. The third state provides a third sampling rate,higher than the second sampling rate. The third state also enables anacceleration measurement queuing capability that stores accelerationmeasurements over a period of time.

During a time period after the first tap is detected, the IMU may bemaintained in this third state. If no further motion is detected duringthe time period, the IMU may be transitioned back to the second state.With this transition, the IMU sampling rate returns to the second rate,and the acceleration queuing capability may also be disabled to savefurther power.

If no motion is detected for a second threshold period of time, the IMUmay be transitioned back from the second state to the first state. Thesampling rate of the IMU may also be reduced from the second rate to thelower first rate as a result of this transition. By modulating thesampling rate of the MU based on motion detected, overall powerconsumption of the IMU may be reduced, while still providing detectionof motion and tap events, including both single tap and double tapevents.

FIG. 1 shows aspects of certain embodiments illustrated by a frontperspective view of glasses 31. The glasses 31 can include a frame 32made from any suitable material such as plastic or metal, including anysuitable shape memory alloy. The frame 32 can have a front piece 33 thatcan include a first or left lens, display or optical element holder 36and a second or right lens, display or optical element holder 37connected by a bridge 38. The front piece 33 additionally includes aleft end portion 41 and a right end portion 42. A first or left opticalelement 43 and a second or right optical element 44 can be providedwithin respective left and right optical element holders 36, 37. Each ofthe optical elements 43, 44 can be a lens, a display, a display assemblyor a combination of the foregoing. Any of the display assembliesdisclosed herein can be provided in the glasses 31.

Frame 32 additionally includes a left arm or temple piece 46 and asecond arm or temple piece 47 coupled to the respective left and rightend portions 41, 42 of the front piece 33 by any suitable means such asa hinge (not shown), so as to be coupled to the front piece 33, orrigidly or fixably secured to the front piece so as to be integral withthe front piece 33. Each of the temple pieces 46 and 47 can include afirst portion 51 that is coupled to the respective end portion 41 or 42of the front piece 33 and any suitable second portion 52 for coupling tothe ear of the user. In one embodiment the front piece 33 can be formedfrom a single piece of material, so as to have a unitary or integralconstruction. In one embodiment, such as illustrated in FIG. 1, theentire frame 32 can be formed from a single piece of material so as tohave a unitary or integral construction.

Glasses 31 can include a computing device, such as computer 61, whichcan be of any suitable type so as to be carried by the frame 32 and, inone embodiment of a suitable size and shape, so as to be at leastpartially disposed in one of the temple pieces 46 and 47. In oneembodiment, as illustrated in FIG. 1, the computer 61 is sized andshaped similar to the size and shape of one of the temple pieces 46, 47and is thus disposed almost entirely if not entirely within thestructure and confines of such temple pieces 46 and 47. In oneembodiment, the computer 61 can be disposed in both of the temple pieces46, 47. The computer 61 can include one or more processors with memory,wireless communication circuitry, and a power source. As describedabove, the computer 61 comprises low-power circuitry, high-speedcircuitry, and a display processor. Various other embodiments mayinclude these elements in different configurations or integratedtogether in different ways. Additional details of aspects of computer 61may be implemented as illustrated by device 210 discussed below.

The computer 61 additionally includes a battery 62 or other suitableportable power supply. In one embodiment, the battery 62 is disposed inone of the temple pieces 46 or 47. In the glasses 31 shown in FIG. 1 thebattery 62 is shown as being disposed in left temple piece 46 andelectrically coupled using connection 74 to the remainder of thecomputer 61 disposed in the right temple piece 47. The one or more inputand output devices can include a connector or port (not shown) suitablefor charging a battery 62 accessible from the outside of frame 32, awireless receiver, transmitter or transceiver (not shown) or acombination of such devices. In various embodiments, the computer 61 andthe battery 62 may consume power as part of glasses operations forcapturing images, transmitting data, or performing other computingprocesses. Such power consumption may result in heat that may impact thedevice as well as a user wearing the device. Embodiments describedherein may function to manage temperature in wearable devices such asglasses 31.

Glasses 31 include cameras 69. Although two cameras are depicted, otherembodiments contemplate the use of a single or additional (i.e., morethan two) cameras. In various embodiments, glasses 31 may include anynumber of input sensors or peripheral devices in addition to cameras 69.Front piece 33 is provided with an outward facing, forward-facing orfront or outer surface 66 that faces forward or away from the user whenthe glasses 31 are mounted on the face of the user, and an oppositeinward-facing, rearward-facing or rear or inner surface 67 that facesthe face of the user when the glasses 31 are mounted on the face of theuser. Such sensors can include inwardly-facing video sensors or digitalimaging modules such as cameras that can be mounted on or providedwithin the inner surface 67 of the front piece 33 or elsewhere on theframe 32 so as to be facing the user, and outwardly-facing video sensorsor digital imaging modules such as cameras 69 that can be mounted on orprovided with the outer surface 66 of the front piece 33 or elsewhere onthe frame 32 so as to be facing away from the user. Such sensors,peripheral devices or peripherals can additionally include biometricsensors, location sensors, or any other such sensors.

Embodiments of this disclosure may provide for reduced power consumptionof the computer 61. For example, in some aspects, the computer 61 mayinclude an accelerometer or inertial measurement unit that is configuredto record accelerations in one or more axis. These accelerations may beused, in some aspects, to detect touch events that may occur on aportion of the glasses 31, such as the frame 32. The accelerometer orinertial measurement unit may consume power. Given a finite life of thebattery 62, it may be desirable to operate the accelerometer in such amanner as to more efficiency consume power while meeting the needs ofone or more applications running on the glasses 31 that utilize theaccelerometer measurements. Embodiments of this disclosure provide forthat reduced power consumption, in some aspects, by specificallytailoring a polling or measurement rate of the accelerometer to theneeds of the application(s) at a particular point in time, as furtherdiscussed below.

FIG. 2 is a block diagram illustrating a networked system 200 includingdetails of a device 210, according to some example embodiments. Incertain embodiments, device 210 may be implemented in glasses 31 of FIG.1 described above. For example, device 210 may be equivalent, in someaspects, to the computer 61.

System 200 includes device 210, client device 290, and server system298. Client device 290 may be a smartphone, tablet, phablet, laptopcomputer, access point, or any other such device capable of connectingwith device 210 using both a low-power wireless connection 225 and ahigh-speed wireless connection 237. Client device 290 is connected toserver system 298 and network 295. The network 295 may include anycombination of wired and wireless connections. Server system 298 may beone or more computing devices as part of a service or network computingsystem. Client device 290 and any elements of server system 298 andnetwork 295 may be implemented using details of software architecture902 or machine 1000 described in FIGS. 9 and 10.

System 200 may optionally include additional peripheral device elements219 and/or a display 211 integrated with device 210. Such peripheraldevice elements 219 may include biometric sensors, additional sensors,or display elements integrated with device 210. Examples of peripheraldevice elements 219 are discussed further with respect to FIGS. 9 and10. For example, peripheral device elements 219 may include any I/Ocomponents 1050 including output components, 1052 motion components1058, or any other such elements described herein. Example embodimentsof a display 211 are discussed in FIGS. 3 and 4.

Device 210 includes inertial measurement unit (IMU) 215, camera 214,video processor 212, interface 216, low-power circuitry 220, andhigh-speed circuitry 230. Camera 214 includes digital camera elementssuch as a charge coupled device, a lens, or any other light capturingelements that may be used to capture data as part of camera 214. In someaspects, the camera 214 may be the camera 69, discussed above withrespect to FIG. 1. While the IMU 215 is shown in FIG. 2 as beingincluded within the device 210, in some aspects, the IMU 215 may be aseparate device, and be operably connected, for example, via acommunications bus or other interconnect technology, the device 210.

Interface 216 refers to any source of a user command that is provided todevice 210. In one implementation, interface 216 is a physical button ona camera that, when depressed, sends a user input signal from interface216 to low power processor 222. A depression of such a camera buttonfollowed by an immediate release may be processed by low power processor222 as a request to capture a single image. A depression of such acamera button for a first period of time may be processed by low-powerprocessor 222 as a request to capture video data while the button isdepressed, and to cease video capture when the button is released, withthe video captured while the button was depressed stored as a singlevideo file. In certain embodiments, the low-power processor 222 may havea threshold time period between the press of a button and a release,such as 500 milliseconds or one second, below which the button press andrelease is processed as an image request, and above which the buttonpress and release is interpreted as a video request. The low powerprocessor 222 may make this determination while the video processor 212is booting. In other embodiments, the interface 216 may be anymechanical switch or physical interface capable of accepting user inputsassociated with a request for data from the camera 214. In otherembodiments, the interface 216 may have a software component, or may beassociated with a command received wirelessly from another source.

Video processor 212 includes circuitry to receive signals from thecamera 214 and process those signals from the camera 214 into a formatsuitable for storage in the memory 234. Video processor 212 isstructured within device 210 such that it may be powered on and bootedunder the control of low-power circuitry 220. Video processor 212 mayadditionally be powered down by low-power circuitry 220. Depending onvarious power design elements associated with video processor 212, videoprocessor 212 may still consume a small amount of power even when it isin an off state. This power will, however, be negligible compared to thepower used by video processor 212 when it is in an on state, and willalso have a negligible impact on battery life. As described herein,device elements in an “off” state are still configured within a devicesuch that low-power processor 222 is able to power on and power down thedevices. A device that is referred to as “off” or “powered down” duringoperation of device 210 does not necessarily consume zero power due toleakage or other aspects of a system design.

In one example embodiment, video processor 212 comprises amicroprocessor integrated circuit (IC) customized for processing sensordata from camera 214, along with volatile memory used by themicroprocessor to operate. In order to reduce the amount of time thatvideo processor 212 takes when powering on to processing data, anon-volatile read only memory (ROM) may be integrated on the IC withinstructions for operating or booting the video processor 212. This ROMmay be minimized to match a minimum size needed to provide basicfunctionality for gathering sensor data from camera 214, such that noextra functionality that would cause delays in boot time are present.The ROM may be configured with direct memory access (DMA) to thevolatile memory of the microprocessor of video processor 212. DMA allowsmemory-to-memory transfer of data from the ROM to system memory of thevideo processor 212 independently of operation of a main controller ofvideo processor 212. Providing DMA to this boot ROM further reduces theamount of time from power on of the video processor 212 until sensordata from the camera 214 can be processed and stored. In certainembodiments, minimal processing of the camera signal from the camera 214is performed by the video processor 212, and additional processing maybe performed by applications operating on the client device 290 orserver system 298.

Low-power circuitry 220 includes low-power processor 222 and low-powerwireless circuitry 224. These elements of low-power circuitry 220 may beimplemented as separate elements or may be implemented on a single IC aspart of a system on a single chip. Low-power processor 222 includeslogic for managing the other elements of the device 210. As describedabove, for example, low power processor 222 may accept user inputsignals from an interface 216. Low-power processor 222 may also beconfigured to receive input signals or instruction communications fromclient device 290 via low-power wireless connection 225. Additionaldetails related to such instructions are described further below.Low-power wireless circuitry 224 includes circuit elements forimplementing a low-power wireless communication system. Bluetooth™Smart, also known as Bluetooth™ low energy, is one standardimplementation of a low power wireless communication system that may beused to implement low-power wireless circuitry 224. In otherembodiments, other low power communication systems may be used.

High-speed circuitry 230 includes high-speed processor 232, memory 234,and high-speed wireless circuitry 236. High-speed processor 232 may beany processor capable of managing high-speed communications andoperation of any general computing system needed for device 210. Highspeed processor 232 includes processing resources needed for managinghigh-speed data transfers on high-speed wireless connection 237 usinghigh-speed wireless circuitry 236. In certain embodiments, thehigh-speed processor 232 executes an operating system such as a LINUXoperating system or other such operating system such as operating system904 of FIG. 9. In addition to any other responsibilities, the high-speedprocessor 232 executing a software architecture for the device 210 isused to manage data transfers with high-speed wireless circuitry 236. Incertain embodiments, high-speed wireless circuitry 236 is configured toimplement Institute of Electrical and Electronic Engineers (IEEE) 802.11communication standards, also referred to herein as Wi-Fi. In otherembodiments, other high-speed communications standards may beimplemented by high-speed wireless circuitry 236.

Memory 234 includes any storage device capable of storing camera datagenerated by the camera 214 and video processor 212. While memory 234 isshown as integrated with high-speed circuitry 230, in other embodiments,memory 234 may be an independent standalone element of the device 210.In certain such embodiments, electrical routing lines may provide aconnection through a chip that includes the high-speed processor 232from the video processor 212 or low-power processor 222 to the memory234. In other embodiments, the high-speed processor 232 may manageaddressing of memory 234 such that the low-power processor 222 will bootthe high-speed processor 232 any time that a read or write operationinvolving memory 234 is needed.

In various embodiments, the IMU 215 and/or the high-speed circuitry 230may consume power as part of the operation of the camera device 210 andin the course of performing one or more functions such as measuringaccelerations, detecting touch events, and other functions. Thedisclosed embodiments may provide for reduced power consumption of theIMU 215 and/or the high speed circuitry 230 when compared to othermethods.

FIGS. 3 and 4 illustrate two embodiments of glasses which includedisplay systems. In various different embodiments, such display systemsmay be integrated with the camera devices discussed above, or may beimplemented as wearable devices without an integrated camera. Inembodiments without a camera, power conservation systems and methodscontinue to operate for the display system and other such systems in amanner similar to what is described above for the video processor anddata transfer elements of the camera devices.

FIG. 3 illustrates glasses 361 having an integrated display 211. Theglasses 361 can be of any suitable type, including glasses 31, and likereference numerals have been used to describe like components of glasses361 and 31. For simplicity, only a portion of the glasses 361 are shownin FIG. 3. Headwear or glasses 361 can optionally include left and rightoptical lenses 362, 563 secured within respective left and right opticalelement holders 36, 37. The glasses 361 can additionally include anysuitable left and right optical elements or assemblies 366, which can besimilar to any of the optical elements or assemblies discussed hereinincluding optical elements 43, 44 of glasses 31. Although only oneoptical assembly 366 is shown in FIG. 3, it is appreciated that anoptical assembly 366 can be provided for both eyes of the user.

In one embodiment, the optical assembly 366 includes any suitabledisplay matrix 367. Such a display matrix 367 can be of any suitabletype, such as a liquid crystal display (LCD), an organic light-emittingdiode (OLED) display, or any other such display. The optical assembly366 also includes an optical layer or layers 368, which can be includelenses, optical coatings, prisms, mirrors, waveguides, and other opticalcomponents in any combination. In the embodiment illustrated in FIG. 3,the optical layer 368 is a prism having a suitable size andconfiguration and including a first surface 371 for receiving light fromdisplay matrix 367 and a second surface 372 for emitting light to theeye of the user. The prism extends over all or at least a portion of theoptical element holder 36, 37 so to permit the user to see the secondsurface 372 of the prism when the eye of the user is viewing through thecorresponding optical element holder 36. The first surface 371 facesupwardly from the frame 32 and the display matrix 367 overlies the prismso that photons and light emitted by the display matrix 367 impinge thefirst surface 371. The prism is sized and shaped so that the light isrefracted within the prism and is directed towards the eye of the userby the second surface 372. In this regard, the second surface 372 can beconvex so as to direct the light towards the center of the eye. Theprism can optionally be sized and shaped so as to magnify the imageprojected by the display matrix 367, and the light travels through theprism so that the image viewed from the second surface 372 is larger inone or more dimensions than the image emitted from the display matrix367.

Glasses 361 can include any suitable computing system, including any ofthe computing devices disclosed herein, such as computer 61, 210 ormachine 1000. In the embodiment of FIG. 3, computer 376 powered by asuitable rechargeable battery (not shown), which can be similar tobattery 62, is provided. Computer 376 can receive a data stream from oneor more image sensors 377, which may be similar to camera 69, or thecamera 214, with image sensors 377 positioned such that the image sensor377 senses the same scene as an eye of a wearer of glasses 361.Additional sensors, such as outwardly-facing geometry sensor 378, can beused for any suitable purpose, including the scanning and capturing ofthree-dimensional geometry that may be used by computer 376 with datafrom image sensors 377 to provide information via digital display matrix367.

Computer 376 may be implemented using the processor elements of thedevice 210, including video processor 212, high-speed circuitry 230, andlow-power circuitry 220. Computer 376 may additionally include anycircuitry needed to power and process information for display matrix367, which may be similar to display 211. In certain embodiments, videoprocessor 212 or high-speed processor 232 may include circuitry to drivedisplay matrix 367. In other embodiments, separate display circuitry maybe integrated with the other elements of computer 376 to enablepresentation of images on display matrix 367.

In various embodiments, the computer 376 may include an initialmeasurement unit, such as IMU 215. The disclosed embodiments mayfunction to reduce power consumption of the computer 376 and/or the MU215.

FIG. 4 illustrates another example embodiment, shown as glasses 491,having another implementation of a display. Just as with glasses 361,glasses 491 can be of any suitable type, including glasses 31, andreference numerals have again been used to describe like components ofglasses 491 and 361. Glasses 491 include optical lenses 492 securedwithin each of the left and right optical element holders 36, 37. Thelens 492 has a front surface 493 and an opposite rear surface 494. Theleft and right end portions 41, 42 of the frame front piece 33 caninclude respective left and right frame extensions 496, 497 that extendrearward from the respective end portions 41, 42. Left and right templepieces 46, 47 are provided, and can either be fixedly secured torespective frame extensions 496, 497 or removably attachable to therespective frame extensions 496, 497. In one embodiment, any suitableconnector mechanism 498 is provided for securing the temple pieces 46,47 to the respective frame extension 496, 497.

Glasses 491 includes computer 401, and just as with computer 376,computer 401 may be implemented using the processor elements of device210, including video processor 212, high-speed circuitry 230, andlow-power circuitry 220, and computer 401 may additionally include anycircuitry needed to power and process information for the integrateddisplay elements.

Sensors 402 include one or more cameras, which may be similar to camera214 and/or other digital sensors that face outward, away from the user.The data feeds from these sensors 402 go to computer 401. In theembodiment of FIG. 4 the computer 401 is disposed within the firstportion 51 of right temple piece 47, although the computer 401 could bedisposed elsewhere in alternative embodiments. In the embodiment of FIG.4, right temple piece 47 includes removable cover section 403 for accessto computer 401 or other electronic components of glasses 491.

Glasses 491 include optical elements or assemblies 405, which may besimilar to any other optical elements or assemblies described herein.One optical assembly 405 is shown, but in other embodiments, opticalassemblies may be provided for both eyes of a user. Optical assembly 405includes laser projector 407, which is a three-color laser projectorusing a scanning mirror or galvanometer. During operation, an opticalsource such as a laser projector is disposed in one of the arms ortemples of the glasses, and is shown in right temple piece 47 of glasses491. The computer 401 connects to the laser projector 407. The opticalassembly 605 includes one or more optical strips 411. The optical strips411 are spaced apart across the width of lens 492, as illustrated bylens 492 in right optical element holder 37 of FIG. 4. In otherembodiments, the optical strips 411 may be spaced apart across a depthof the lens 492 between the front surface 493 and the rear surface 494of lens 492 as shown in the partial view of lens 492 in the top cornerof FIG. 4.

During operation, computer 401 sends data to laser projector 407. Aplurality of light paths 412 are depicted, showing the paths ofrespective photons emitted by the laser projector 407. The path arrowsillustrate how lenses or other optical elements direct the photons onpaths 412 that take the photons from the laser projector 407 to the lens492. As the photons then travel across the lens 492, the photonsencounter a series of optical strips 411. When a particular photonencounters a particular optical strip 411, it is either redirectedtowards the user's eye, or it passes to the next optical strip 411.Specific photons or beams of light may be controlled by a combination ofmodulation of laser projector 407 and modulation of optical strips 411.Optical strips 411 may, in certain embodiments, be controlled throughmechanical, acoustic, or electromagnetic signals initiated by computer401.

In one example implementation of the optical strips 411, each strip 411can use Polymer Dispersed Liquid Crystal to be opaque or transparent ata given instant of time, per software command from computer 401. In adifferent example implementation of the optical strips 411, each opticalstrip 411 can have a specific wavelength of light that it redirectstoward the user, passing all the other wavelengths through to the nextoptical strip 411. In a different example implementation of the opticalstrips 411, each strip 411 can have certain regions of the strip 411that cause redirection with other regions passing light, and the laserprojector 407 can use high precision steering of the light beams totarget the photons at the desired region of the particular intendedoptical strip 411.

In the embodiment of lens 492 illustrated in the top left of FIG. 4,optical strips 411 are disposed in and spaced apart along the width of afirst layer 416 of the lens 492, which is secured in a suitable mannerto a second layer 417 of the lens 492. In one embodiment, the frontsurface 493 is formed by the second layer 417 and the rear surface 494is formed by the first layer 416. The second layer 417 can be providedwith reflective coatings on at least a portion of the surfaces thereofso that the laser light bounces off such surfaces so as to travel alongthe layer 417 until the light encounters a strip 411 provided in thefirst layer 416, and is either redirected towards the eye of the user orcontinues on to the next strip 411 in the manner discussed above.

In various embodiments, the computer 401 may include an accelerometer orinertial measurement unit, such as the IMU 215 discussed above withrespect to FIG. 2. The IMU and/or computer 401 may consume power as partof glasses 491 operations for capturing images, transmitting data, orperforming other computing processes. Embodiments described herein mayfunction to reduce power consumption of the computer 401 and/or IMU 215in wearable devices such as glasses 491.

FIG. 5 is a state transition diagram that may be implemented in at leastsome of the disclosed embodiments. For example, in some aspects, thestates illustrated in FIG. 5 may be implemented in the high speedcircuitry 230 discussed above with respect to FIG. 2, and in particularto the control of the IMU 215 in some aspects. In some aspects,instructions stored in the memory 234 may configure the high speedprocessor 232 in some aspects to control the IMU 215.

The state transition diagram shows three states 502 a-c. State 502 a isconsidered a no-motion state, in that state 502 a is entered if nomotion is detected by the IMU 215 for a period of time. For example,FIG. 5 shows state 502 a being entered if no motion is detected withinten (10) seconds. While in the state 502 a, a sampling rate of the IMU215 is set to a first rate. While operating at the first rate, the IMU215 may be unable to detect a direction of motion, but may be able todetect that motion occurred in some direction. Because the first rate isrelatively low, the IMU 215 consumes a relatively low amount of power inthe first state 502 a.

If motion is detected, the IMU 215 is transitioned to a second state,called the “Active” state 502 b. While in the “active” state, the IMU215 sampling rate is set to a second rate, which is higher than thefirst rate. Thus, the IMU 215 may consume a greater amount of powerwhile in the “active” state 502 b than it did when it was in the“no-motion” state 502 a, which has a lower sampling rate. While in the“active” state 502 b, the IMU 215 may be able to detect a tap event. Forexample, a tap event may be a tap along a side of the glasses 31, 361 or491.

Upon detecting a tap, the IMU 215 may be transitioned from the “active”state 502 b to the state 502 c, called the “Second-Tap Detect state.”While in the state 502 c, the IMU 215 may have a third sampling rate,higher than the second sampling rate. The third state may also enable anacceleration measurement storage capability, which stores a number ofacceleration measurements in a queue. Maintaining this queue requiresadditional power. Thus, due to the faster sampling rate and accelerationmeasurement queue, the third state 502 c may consume more power than thesecond state 502 b. Because the IMU 215 is sampling at a higher thirdrate, the IMU may be able to detect “double tap” events, which includetwo taps within a predetermined time period. If a second tap is detectedwhile the IMU 215 is in the state 502 c, a predetermined action 520 maybe taken. For example, FIG. 5 shows that a battery check LED animationmay be shown. The IMU 215 may then be transitioned back to state 502 b.

If no tap is detected while in the state 502 c, within a predeterminedamount of time, the IMU 215 may be transitioned back to the state 502 b.

FIG. 6 is a block diagram of an example IMU 215. The example IMU 215 ofFIG. 6 includes an interface 601, a clock 602, a processor 604, a memory606, and three motion sensors 608 a-c. The interface 601 may provide away for the processor 604 to receive commands. For example, theinterface 601 may allow the processor 604 to receive commands from thehigh speed processor 232 in some aspects. The interface 601 may alsoprovide a way for the processor 604 to provide acceleration data outsidethe IMU 215. For example, the processor 604 may send accelerationmeasurements from the IMU 215 to the processor 232 via the interface 601in some aspects. The clock 602 may synchronize the processor 604. Forexample, the clock 602 may signal the processor 604 at a periodicinterval. The signal from the clock 602 may be utilized, in someaspects, by the processor 604 to determine a rate at which to poll themotion sensors 608 a-c, as discussed further below.

In some aspects, the memory 606 may store instructions that configurethe processor 604 to perform one or more functions of the IMU 215. Insome aspects, the memory 606 may store one or more accelerationmeasurements received from one or more of the motion sensors. Forexample, the memory 606 may store a queue of acceleration measurementsfrom the motion sensors 608 a-c in some aspects.

The processor 604 may poll the three motion sensors 608 a-c at a rate.The rate may be variable, and may be set by commands received over theinterface 601. For example, in some aspects, the high speed processor232 may set a rate of that the processor 604 is to poll the three motionsensor 608 a-c. Each of the motion sensors 608 a-c may be configured tosense motion along a different axis. For example, motion sensor 608 amay be configured to sense motion along an X axis, motion sensor 608 bmay be configured to sense motion along a Y axis orthogonal to the Xaxis, and motion sensor 608 c may be configured to sense motion along aZ axis, which is orthogonal to both the X and Y axis.

FIG. 7 is a data flow diagram of one exemplary method of training amodel to detect tap inputs based on acceleration data. In some aspects,the classifier 730, discussed in more detail below, may identify one ormore accelerations that represent a tap input, and one or moreaccelerations that do not represent a tap input. In some aspects, theclassifier 730 may be utilized by block 820 and/or block 855, discussedbelow with respect to FIG. 8, to identify a tap input. In some aspects,one or more of the functions and/or dataflows described below withrespect to dataflow 700 and FIG. 7 may be performed by the processor232, discussed above with respect to FIG. 2. For example, instructionsstored in the memory 234, may configure the processor 232 to perform oneor more of the data flows and/or functions of data flow 700 discussedbelow.

FIG. 7 shows a training database 702. The training database 702 includesa plurality of training acceleration measurements 705. Also shown is anannotation database 706. The annotation database 706 stores annotations708 that indicate which of the training acceleration measurements 705indicate tap inputs and which of the training acceleration measurements705 do not represent tap inputs.

A model builder 710 may read the acceleration measurements 705 andannotation data 708 to generate a model database 720. The model database720 may include data representing characteristics of the tap inputs andnon-tap inputs within the acceleration data 705. For example, in someaspects, the model builder 710 may apply multiple filters to theacceleration measurements 705 and generate filter outputs. The filteroutputs may be stored in the model database 720 in some aspects. Themodel database 720 may then be utilized to determine acceleration datathat represents tap inputs and acceleration data that does not representa tap input within the acceleration measurements 705.

The classifier 730 may then read the model data 720 to determine whetheracceleration data 725 corresponds to a tap event or does not correspondto a tap event. For example, in some aspects, the classifier 730 mayapply various filters to the acceleration data 725, and compare filterresponses to filter responses stored in the model data 1220. Byidentifying similarities between the filter responses from accelerationmeasurements annotated as tap inputs from the training data base 702,and filter responses from the acceleration data 725, the classifier 730may generate output 740 indicating whether the acceleration data 725 isa tap input or is not a tap input.

FIG. 8 is a flowchart of a method for managing a sampling rate of aninertial measurement unit. In some aspects, one or more functions ofprocess 800 discussed below may be performed by the IMU managementapplication 967, discussed below with respect to FIG. 9. In someaspects, the IMU management application 967 may be running on theprocessor 232, discussed above with respect to FIG. 2. In some aspects,the processors 1010 discussed below with respect to FIG. 10, may beequivalent to the processor 232 discussed above with respect to FIG. 2.Furthermore, memory 1030, discussed below with respect to FIG. 10, maybe equivalent to memory 234, discussed above with respect to FIG. 2.Thus, instructions 1016, discussed below with respect to FIG. 10, mayconfigure one or more hardware processors, such as hardware processors1010 discussed below with respect to FIG. 10, to perform one or more ofthe functions of process 800 discussed below. In some other embodiments,one or more of the functions of process 800 discussed below may beperformed by the computer 61, the device 210, or the computers 376and/or 401 of FIGS. 1-4 respectively.

In block 805, a device may boot. For example, in some aspects, thedevice may be the IMU 215. In response to the boot event of block 805,process 800 moves to block 810, where the device enters an active powerstate. Block 810 includes setting a sampling rate of the device to afirst sampling rate. In some aspects, this rate may be high enough toprovide for detection of single tap events. In some aspects, this ratemay not be high enough to provide for detection of double tap events. Inthe active power state, the device may consume power at a first powerconsumption rate. The first power consumption rate may be based on thefirst sampling rate. As discussed above with respect to FIG. 5, theactive state may not include enabling of an acceleration managementqueue. Thus, a history of acceleration measurements available fordetection of a tap event may be limited. Block 820 determines if a tapis detected. For example, in some aspects, block 820 may analyzeacceleration data received at the first sampling rate from the IMU, anddetermine if the acceleration data includes a tap event. In someaspects, this determination may rely on a regression model to make thedetermination, for example, as discussed above with respect to FIG. 7.For example, the acceleration data analyzed in block 820 may berepresented by block 725 in data flow 700.

If a tap is not detected in block 820, process 800 moves to decisionblock 830, which determines whether a predetermined amount of time haselapsed since the device entered the active power state in block 810. Ifthe predetermined amount of time has not elapsed, process 800 moves towait block 835. Wait block 835 may wait a period of time indicated bythe first sampling rate. For example, if decision block 820 samples theacceleration sensors 608 a-c, the amount of waiting performed by waitblock 835 may determine a frequency of the sampling. After the wait iscomplete in block 835, processing returns to decision block 820.

If decision block 830 determines the time has elapsed, process 800 movesto block 840, where the device enters a low power state. Block 840 setsa sampling rate of the device to a second rate. The second rate isslower than the first rate set in block 810. After entering state 840and sampling at the second rate, the device will have a second powerconsumption rate which is lower than the first power consumption ratethe device has in the active power state of block 810. Once in the lowpower state of block 840, the device may be unable to detect tap inputs.Instead, the second sampling rate may support detection of motion, butmay not support detection of any directional information with respect tothe accelerations.

Process 800 moves from block 840 to block 845, which determines if anymotion is detected. As discussed above, the lower sampling rate of block840 may not support detection of tap events. The lower sampling rate maysupport detection of motion. If no motion is detected, process 800 movesfrom decision block 845 to wait block 847, which waits for a period oftime. The wait period of block 847 may provide the second sampling rateof block 840 (the low power state). Thus, the wait period of block 847may be longer than the wait period of block 835 in some aspects. Afterthe wait period of block 847 completes, process returns to decisionblock 845. If motion is detected in block 845, process 800 moves fromblock 845 to block 810, where the active power state is reentered inblock 810.

Returning to the discussion of decision block 820, block 820 may utilizea regression model in some aspects to determine whether a tap has beendetected. For example, block 820 may analyze acceleration data, such asacceleration data 725, and determine, via classifier 730, whether a tapinput has been detected based on the acceleration data. If a tap hasbeen detected, process 800 moves from decision block 820 to block 850,which enters a third state named the “2^(nd) tap detect” state. Block850 may increase the sampling rate of the IMU to a third rate. The thirdrate is faster than the first rate of block 810 and of the second rateof block 840. The third sampling rate may provide for detection of adouble tap event. Block 850 may also activate an accelerationmeasurement storage capability in the IMU. For example, as discussedabove with respect to FIG. 6, in some aspects, the IMU 215 may beconfigured to store acceleration measurements in the memory 606. In someaspects, any number of measurements may be stored. In some aspects, thestorage may be limited based on a size of the memory 606. In someaspects, 1, 2, 3, 4, 5, 10, 15, 20, 21, 25, 30 or any number ofmeasurements may be stored.

Process 800 moves from block 850 to decision block 855, which determinesif a second tap is detected. In some aspects, decision block 855 mayattempt to detect a tap event by analyzing acceleration data read fromacceleration sensors (e.g. 608 a-c) via a trained classifier, such asclassifier 730 discussed above. If decision block 855 detects a tapevent, process 800 moves from decision block 855 to block 860, whichperforms an action. In some aspects, the action is to display a batterycheck LED animation. Other types of actions are contemplated. After theaction is performed, process 800 moves from block 860 to block 810.

Returning to the discussion of decision block 855, if no tap event isdetected, process 800 moves from block 855 to decision block 865, whichdetermines if a predetermined amount of time has elapsed since enteringthe 2^(nd) tap detect state of block 850. In some aspects, thepredetermined amount of time of block 865 is either the same ordifferent than the predetermined amount of time of block 830. If thetime has not elapsed, process 800 moves from block 865 to wait block870. Block 870 may wait a period of time that effectively defines thethird sampling rate of block 850. Thus, the waiting period of block 870may be shorter than the waiting periods of either block 835 or block847. After the waiting period of bock 870 is complete, process 800 movesfrom block 870 to decision block 855. Returning to the discussion ofdecision block 865, if the amount of time has elapsed, process 800 movesfrom decision block 865 to block 810, which reenters the active state.

While the methods described above present operations in a particularorder, it will be appreciated that alternate embodiments may operatewith certain operations occurring simultaneously or in a differentorder.

FIG. 9 is a block diagram 900 illustrating an architecture of softwarearchitecture 902, which can be installed on any one or more of thedevices described above. FIG. 9 is merely a non-limiting example of asoftware architecture, and it will be appreciated that many otherarchitectures can be implemented to facilitate the functionalitydescribed herein. In various embodiments, the software architecture 902is implemented by hardware such as computer 61, device 210, computer376, and/or computer 401 of FIGS. 1, 2, 3, and 4 respectively. In someaspects, the software 902 may be executed by a machine 1000 of FIG. 10,discussed below. The software architecture 902 may include a stack oflayers where each layer may provide a particular functionality. Forexample, the software architecture 902 may include one or more layerssuch as an operating system 904, libraries 906, frameworks 908, andapplications 910. Operationally, the applications 910 invoke applicationprogramming interface (API) calls 912 through the software stack andreceive messages 914 in response to the API calls 912, consistent withsome embodiments. In various embodiments, any client device 290, servercomputer of a server system 298, or any other device described hereinmay operate using elements of software architecture 902. Devices such asthe device 210 may additionally be implemented using aspects of softwarearchitecture 902, with the architecture adapted for operating usinglow-power circuitry (e.g., low-power circuitry 220) and high-speedcircuitry (e.g., high-speed circuitry 230) as described herein.

In various implementations, the operating system 904 manages hardwareresources and provides common services. The operating system 904includes, for example, a kernel 920, services 922, and drivers 924. Thekernel 920 acts as an abstraction layer between the hardware and theother software layers consistent with some embodiments. For example, thekernel 920 provides memory management, processor management (e.g.,scheduling), component management, networking, and security settings,among other functionality. The services 922 can provide other commonservices for the other software layers. The drivers 924 are responsiblefor controlling or interfacing with the underlying hardware, accordingto some embodiments. For instance, the drivers 924 can include displaydrivers, camera drivers, BLUETOOTH® or BLUETOOTH® Low Energy drivers,flash memory drivers, serial communication drivers (e.g., UniversalSerial Bus (USB) drivers), WI-FI® drivers, audio drivers, powermanagement drivers, and so forth. In certain implementations of a devicesuch as the device 210, low-power circuitry may operate using drivers924 that only contain BLUETOOTH® Low Energy drivers and basic logic formanaging communications and controlling other devices, with otherdrivers operating with high-speed circuitry.

In some embodiments, the libraries 906 provide a low-level commoninfrastructure utilized by the applications 910. The libraries 906 caninclude system libraries 930 (e.g., C standard library) that can providefunctions such as memory allocation functions, string manipulationfunctions, mathematic functions, and the like. In addition, thelibraries 906 can include API libraries 932 such as media libraries(e.g., libraries to support presentation and manipulation of variousmedia formats such as Moving Picture Experts Group-4 (MPEG4), AdvancedVideo Coding (H.264 or AVC), Moving Picture Experts Group Layer-3 (MP3),Advanced Audio Coding (AAC), Adaptive Multi-Rate (AMR) audio codec,Joint Photographic Experts Group (JPEG or JPG), or Portable NetworkGraphics (PNG)), graphics libraries (e.g., an OpenGL framework used torender in two dimensions (2D) and three dimensions (3D) in a graphiccontent on a display), database libraries (e.g., SQLite to providevarious relational database functions), web libraries (e.g., WebKit toprovide web browsing functionality), and the like. The libraries 906 canalso include a wide variety of other libraries 934 to provide many otherAPIs to the applications 910.

The frameworks 908 provide a high-level common infrastructure that canbe utilized by the applications 910, according to some embodiments. Forexample, the frameworks 908 provide various graphic user interface (GUI)functions, high-level resource management, high-level location services,and so forth. The frameworks 908 can provide a broad spectrum of otherAPIs that can be utilized by the applications 910, some of which may bespecific to a particular operating system or platform.

In an example embodiment, the applications 910 may include a homeapplication 950, a contacts application 952, a browser application 954,a location application 958, a media application 960, a messagingapplication 962, and a broad assortment of other applications such as athird party application 966. According to some embodiments, theapplications 910 are programs that execute functions defined in theprograms. Various programming languages can be employed to create one ormore of the applications 910, structured in a variety of manners, suchas object-oriented programming languages (e.g., Objective-C, Java, orC++) or procedural programming languages (e.g., C or assembly language).In a specific example, the third party application 966 (e.g., anapplication developed using the ANDROID™ or IOS™ software developmentkit (SDK) by an entity other than the vendor of the particular platform)may be mobile software running on a mobile operating system such asIOS™, ANDROID™, WINDOWS® Phone, or another mobile operating systems. Inthis example, the third party application 966 can invoke the API calls912 provided by the operating system 904 to facilitate functionalitydescribed herein.

Embodiments described herein may particularly interact with an inertialmeasurement unit (IMU) management application 967. Such an application967 may interact with motion component 1058, discussed below withrespect to FIG. 10, to provide detection of touch inputs while managingpower consumption, as discussed above, for example, with respect toFIGS. 5 and/or 8.

The software architecture of FIG. 9 illustrates an example architecturethat may be implemented in some embodiments by a wearable deviceexecuting a mobile operating system (e.g., IOS™, ANDROID™, WINDOWS®Phone, or other mobile operating systems), consistent with someembodiments. In one embodiment, the wearable device detects touch inputsfrom the user via the information provided by an acceleration sensor orinertial measurement unit.

FIG. 10 shows a diagrammatic representation of a machine 1000 in theexample form of a computer system, within which instructions 1016 (e.g.,software, a program, an application, an applet, an app, or otherexecutable code) for causing the machine 1000 to perform any one or moreof the methodologies discussed herein can be executed. In alternativeembodiments, the machine 1000 operates as a standalone device or can becoupled (e.g., networked) to other machines. In a networked deployment,the machine 1000 may operate in the capacity of a server machine or aclient machine in a server-client network environment, or as a peermachine in a peer-to-peer (or distributed) network environment. Themachine 1000 can comprise, but not be limited to, a server computer, aclient computer, a personal computer (PC), a tablet computer, a laptopcomputer, a netbook, a set-top box (STB), a personal digital assistant(PDA), an entertainment media system, a cellular telephone, a smartphone, a mobile device, a wearable device (e.g., a smart watch), a smarthome device (e.g., a smart appliance), other smart devices, a webappliance, a network router, a network switch, a network bridge, or anymachine capable of executing the instructions 1016, sequentially orotherwise, that specify actions to be taken by the machine 1000.Further, while only a single machine 1000 is illustrated, the term“machine” shall also be taken to include a collection of machines 1000that individually or jointly execute the instructions 1016 to performany one or more of the methodologies discussed herein.

In various embodiments, the machine 1000 comprises processors 1010,memory 1030, and I/O components 1050, which can be configured tocommunicate with each other via a bus 1002. In an example embodiment,the processors 1010 (e.g., a Central Processing Unit (CPU), a ReducedInstruction Set Computing (RISC) processor, a Complex Instruction SetComputing (CISC) processor, a Graphics Processing Unit (GPU), a DigitalSignal Processor (DSP), an Application Specific Integrated Circuit(ASIC), a Radio-Frequency Integrated Circuit (RFIC), another processor,or any suitable combination thereof) include, for example, a processor1012 and a processor 1014 that may execute the instructions 1016. Theterm “processor” is intended to include multi-core processors that maycomprise two or more independent processors (also referred to as“cores”) that can execute instructions contemporaneously. Although FIG.10 shows multiple processors 1010, the machine 1000 may include a singleprocessor with a single core, a single processor with multiple cores(e.g., a multi-core processor), multiple processors with a single core,multiple processors with multiples cores, or any combination thereof.

The memory 1030 comprises a main memory 1032, a static memory 1034, anda storage unit 1036 accessible to the processors 1010 via the bus 1002,according to some embodiments. The storage unit 1036 can include amachine-readable medium 1038 on which are stored the instructions 1016embodying any one or more of the methodologies or functions describedherein. The instructions 1016 can also reside, completely or at leastpartially, within the main memory 1032, within the static memory 1034,within at least one of the processors 1010 (e.g., within the processor'scache memory), or any suitable combination thereof, during executionthereof by the machine 1000. Accordingly, in various embodiments, themain memory 1032, the static memory 1034, and the processors 1010 areconsidered machine-readable media 1038.

As used herein, the term “memory” refers to a machine-readable medium1038 able to store data temporarily or permanently and may be taken toinclude, but not be limited to, random-access memory (RAM), read-onlymemory (ROM), buffer memory, flash memory, and cache memory. While themachine-readable medium 1038 is shown in an example embodiment to be asingle medium, the term “machine-readable medium” should be taken toinclude a single medium or multiple media (e.g., a centralized ordistributed database, or associated caches and servers) able to storethe instructions 1016. The term “machine-readable medium” shall also betaken to include any medium, or combination of multiple media, that iscapable of storing instructions (e.g., instructions 1016) for executionby a machine (e.g., machine 1000), such that the instructions, whenexecuted by one or more processors of the machine 1000 (e.g., processors1010), cause the machine 1000 to perform any one or more of themethodologies described herein. Accordingly, a “machine-readable medium”refers to a single storage apparatus or device, as well as “cloud-based”storage systems or storage networks that include multiple storageapparatus or devices. The term “machine-readable medium” shallaccordingly be taken to include, but not be limited to, one or more datarepositories in the form of a solid-state memory (e.g., flash memory),an optical medium, a magnetic medium, other non-volatile memory (e.g.,Erasable Programmable Read-Only Memory (EPROM)), or any suitablecombination thereof. The term “machine-readable medium” specificallyexcludes non-statutory signals per se.

The I/O components 1050 include a wide variety of components to receiveinput, provide output, produce output, transmit information, exchangeinformation, capture measurements, and so on. In general, it will beappreciated that the I/O components 1050 can include many othercomponents that are not shown in FIG. 10. The I/O components 1050 aregrouped according to functionality merely for simplifying the followingdiscussion, and the grouping is in no way limiting. In various exampleembodiments, the I/O components 1050 include output components 1052 andinput components 1054. The output components 1052 include visualcomponents (e.g., a display such as a plasma display panel (PDP), alight emitting diode (LED) display, a liquid crystal display (LCD), aprojector, or a cathode ray tube (CRT)), acoustic components (e.g.,speakers), haptic components (e.g., a vibratory motor), other signalgenerators, and so forth. The input components 1054 include alphanumericinput components (e.g., a keyboard, a touch screen configured to receivealphanumeric input, a photo-optical keyboard, or other alphanumericinput components), point-based input components (e.g., a mouse, atouchpad, a trackball, a joystick, a motion sensor, or other pointinginstruments), tactile input components (e.g., a physical button, a touchscreen that provides location and force of touches or touch gestures, orother tactile input components), audio input components (e.g., amicrophone), and the like.

In some further example embodiments, the I/O components 1050 includebiometric components 1056, motion components 1058, environmentalcomponents 1060, or position components 1062, among a wide array ofother components. For example, the biometric components 1056 includecomponents to detect expressions (e.g., hand expressions, facialexpressions, vocal expressions, body gestures, or eye tracking), measurebiosignals (e.g., blood pressure, heart rate, body temperature,perspiration, or brain waves), identify a person (e.g., voiceidentification, retinal identification, facial identification,fingerprint identification, or electroencephalogram basedidentification), and the like. The motion components 1058 includeacceleration sensor components (e.g., accelerometer), gravitation sensorcomponents, rotation sensor components (e.g., gyroscope), and so forth.The environmental components 1060 include, for example, illuminationsensor components (e.g., photometer), temperature sensor components(e.g., one or more thermometers that detect ambient temperature),humidity sensor components, pressure sensor components (e.g.,barometer), acoustic sensor components (e.g., one or more microphonesthat detect background noise), proximity sensor components (e.g.,infrared sensors that detect nearby objects), gas sensor components(e.g., machine olfaction detection sensors, gas detection sensors todetect concentrations of hazardous gases for safety or to measurepollutants in the atmosphere), or other components that may provideindications, measurements, or signals corresponding to a surroundingphysical environment. The environmental components, such as thetemperature sensor components that detect ambient temperature, may beutilized to manage the temperature of electronic components discussedherein.

The position components 1062 include location sensor components (e.g., aGlobal Positioning System (GPS) receiver component), altitude sensorcomponents (e.g., altimeters or barometers that detect air pressure fromwhich altitude may be derived), orientation sensor components (e.g.,magnetometers), and the like.

Communication can be implemented using a wide variety of technologies.The I/O components 1050 may include communication components 1064operable to couple the machine 1000 to a network 1080 or devices 1070via a coupling 1082 and a coupling 1072, respectively. For example, thecommunication components 1064 include a network interface component oranother suitable device to interface with the network 1080. In furtherexamples, communication components 1064 include wired communicationcomponents, wireless communication components, cellular communicationcomponents, Near Field Communication (NFC) components, BLUETOOTH®components (e.g., BLUETOOTH® Low Energy), WI-FI® components, and othercommunication components to provide communication via other modalities.The devices 1070 may be another machine or any of a wide variety ofperipheral devices (e.g., a peripheral device coupled via a UniversalSerial Bus (USB)). As discussed above, in some aspects, the disclosedmethods and systems may manage the transmission bandwidth of one or moreof the wireless components (e.g. WiFi) and/or Bluetooth components inorder to control an operating temperature of a device, such as thedevice 1000. In some aspects, the communication components 1064 includedthe low power circuitry 220 and/or high speed circuitry 230.

In some embodiments, the communication components 1064 detectidentifiers or include components operable to detect identifiers. Forexample, the communication components 1064 include Radio FrequencyIdentification (RFID) tag reader components, NFC smart tag detectioncomponents, optical reader components (e.g., an optical sensor to detecta one-dimensional bar codes such as a Universal Product Code (UPC) barcode, multi-dimensional bar codes such as a Quick Response (QR) code,Aztec Code, Data Matrix, Dataglyph, MaxiCode, PDF417, Ultra Code,Uniform Commercial Code Reduced Space Symbology (UCC RSS)-2D bar codes,and other optical codes), acoustic detection components (e.g.,microphones to identify tagged audio signals), or any suitablecombination thereof. In addition, a variety of information can bederived via the communication components 1064, such as location viaInternet Protocol (IP) geo-location, location via WI-FI® signaltriangulation, location via detecting an BLUETOOTH® or NFC beacon signalthat may indicate a particular location, and so forth.

Transmission Medium

In various example embodiments, one or more portions of the network 1080can be an ad hoc network, an intranet, an extranet, a virtual privatenetwork (VPN), a local area network (LAN), a wireless LAN (WLAN), a widearea network (WAN), a wireless WAN (WWAN), a metropolitan area network(MAN), the Internet, a portion of the Internet, a portion of the PublicSwitched Telephone Network (PSTN), a plain old telephone service (POTS)network, a cellular telephone network, a wireless network, a WI-FI®network, another type of network, or a combination of two or more suchnetworks. For example, the network 1080 or a portion of the network 1080may include a wireless or cellular network, and the coupling 1082 may bea Code Division Multiple Access (CDMA) connection, a Global System forMobile communications (GSM) connection, or another type of cellular orwireless coupling. In this example, the coupling 1082 can implement anyof a variety of types of data transfer technology, such as SingleCarrier Radio Transmission Technology (1×RTT), Evolution-Data Optimized(EVDO) technology, General Packet Radio Service (GPRS) technology,Enhanced Data rates for GSM Evolution (EDGE) technology, thirdGeneration Partnership Project (3GPP) including 3G, fourth generationwireless (4G) networks, Universal Mobile Telecommunications System(UMTS), High Speed Packet Access (HSPA), Worldwide Interoperability forMicrowave Access (WiMAX), Long Term Evolution (LTE) standard, othersdefined by various standard-setting organizations, other long rangeprotocols, or other data transfer technology.

In example embodiments, the instructions 1016 are transmitted orreceived over the network 1080 using a transmission medium via a networkinterface device (e.g., a network interface component included in thecommunication components 1064) and utilizing any one of a number ofwell-known transfer protocols (e.g., Hypertext Transfer Protocol(HTTP)). Similarly, in other example embodiments, the instructions 1016are transmitted or received using a transmission medium via the coupling1072 (e.g., a peer-to-peer coupling) to the devices 1070. The term“transmission medium” shall be taken to include any intangible mediumthat is capable of storing, encoding, or carrying the instructions 1016for execution by the machine 1000, and includes digital or analogcommunications signals or other intangible media to facilitatecommunication of such software.

Furthermore, the machine-readable medium 1038 is non-transitory (inother words, not having any transitory signals) in that it does notembody a propagating signal. However, labeling the machine-readablemedium 1038 “non-transitory” should not be construed to mean that themedium is incapable of movement; the medium 1038 should be considered asbeing transportable from one physical location to another. Additionally,since the machine-readable medium 1038 is tangible, the medium 1038 maybe considered to be a machine-readable device.

Language

Throughout this specification, plural instances may implementcomponents, operations, or structures described as a single instance.Although individual operations of one or more methods are illustratedand described as separate operations, one or more of the individualoperations may be performed concurrently, and nothing requires that theoperations be performed in the order illustrated. Structures andfunctionality presented as separate components in example configurationsmay be implemented as a combined structure or component. Similarly,structures and functionality presented as a single component may beimplemented as separate components. These and other variations,modifications, additions, and improvements fall within the scope of thesubject matter herein.

Although an overview of the inventive subject matter has been describedwith reference to specific example embodiments, various modificationsand changes may be made to these embodiments without departing from thebroader scope of embodiments of the present disclosure. Such embodimentsof the inventive subject matter may be referred to herein, individuallyor collectively, by the term “invention” merely for convenience andwithout intending to voluntarily limit the scope of this application toany single disclosure or inventive concept if more than one is, in fact,disclosed.

The embodiments illustrated herein are described in sufficient detail toenable those skilled in the art to practice the teachings disclosed.Other embodiments may be used and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. The Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

As used herein, the term “or” may be construed in either an inclusive orexclusive sense. Moreover, plural instances may be provided forresources, operations, or structures described herein as a singleinstance. Additionally, boundaries between various resources,operations, modules, engines, and data stores are somewhat arbitrary,and particular operations are illustrated in a context of specificillustrative configurations. Other allocations of functionality areenvisioned and may fall within a scope of various embodiments of thepresent disclosure. In general, structures and functionality presentedas separate resources in the example configurations may be implementedas a combined structure or resource. Similarly, structures andfunctionality presented as a single resource may be implemented asseparate resources. These and other variations, modifications,additions, and improvements fall within a scope of embodiments of thepresent disclosure as represented by the appended claims. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense.

Certain embodiments are described herein as including logic or a numberof components, modules, elements, or mechanisms. Such modules canconstitute either software modules (e.g., code embodied on amachine-readable medium or in a transmission signal) or hardwaremodules. A “hardware module” is a tangible unit capable of performingcertain operations and can be configured or arranged in a certainphysical manner. In various example embodiments, one or more computersystems (e.g., a standalone computer system, a client computer system,or a server computer system) or one or more hardware modules of acomputer system (e.g., a processor or a group of processors) isconfigured by software (e.g., an application or application portion) asa hardware module that operates to perform certain operations asdescribed herein.

In some embodiments, a hardware module is implemented mechanically,electronically, or any suitable combination thereof. For example, ahardware module can include dedicated circuitry or logic that ispermanently configured to perform certain operations. For example, ahardware module can be a special-purpose processor, such as aField-Programmable Gate Array (FPGA) or an Application SpecificIntegrated Circuit (ASIC). A hardware module may also includeprogrammable logic or circuitry that is temporarily configured bysoftware to perform certain operations. For example, a hardware modulecan include software encompassed within a general-purpose processor orother programmable processor. It will be appreciated that the decisionto implement a hardware module mechanically, in dedicated andpermanently configured circuitry, or in temporarily configured circuitry(e.g., configured by software) can be driven by cost and timeconsiderations.

Accordingly, the phrase “hardware module” should be understood toencompass a tangible entity, be that an entity that is physicallyconstructed, permanently configured (e.g., hardwired), or temporarilyconfigured (e.g., programmed) to operate in a certain manner or toperform certain operations described herein. As used herein,“hardware-implemented module” refers to a hardware module. Consideringembodiments in which hardware modules are temporarily configured (e.g.,programmed), each of the hardware modules need not be configured orinstantiated at any one instance in time. For example, where a hardwaremodule comprises a general-purpose processor configured by software tobecome a special-purpose processor, the general-purpose processor may beconfigured as respectively different special-purpose processors (e.g.,comprising different hardware modules) at different times. Software canaccordingly configure a particular processor or processors, for example,to constitute a particular hardware module at one instance of time andto constitute a different hardware module at a different instance oftime.

Hardware modules can provide information to, and receive informationfrom, other hardware modules. Accordingly, the described hardwaremodules can be regarded as being communicatively coupled. Where multiplehardware modules exist contemporaneously, communications can be achievedthrough signal transmission (e.g., over appropriate circuits and buses)between or among two or more of the hardware modules. In embodiments inwhich multiple hardware modules are configured or instantiated atdifferent times, communications between such hardware modules may beachieved, for example, through the storage and retrieval of informationin memory structures to which the multiple hardware modules have access.For example, one hardware module performs an operation and stores theoutput of that operation in a memory device to which it iscommunicatively coupled. A further hardware module can then, at a latertime, access the memory device to retrieve and process the storedoutput. Hardware modules can also initiate communications with input oroutput devices, and can operate on a resource (e.g., a collection ofinformation).

The various operations of example methods described herein can beperformed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors constitute processor-implemented modulesthat operate to perform one or more operations or functions describedherein. As used herein, “processor-implemented module” refers to ahardware module implemented using one or more processors.

Similarly, the methods described herein can be at least partiallyprocessor-implemented, with a particular processor or processors beingan example of hardware. For example, at least some of the operations ofa method can be performed by one or more processors orprocessor-implemented modules. Moreover, the one or more processors mayalso operate to support performance of the relevant operations in a“cloud computing” environment or as a “software as a service” (SaaS).For example, at least some of the operations may be performed by a groupof computers (as examples of machines including processors), with theseoperations being accessible via a network (e.g., the Internet) and viaone or more appropriate interfaces (e.g., an Application ProgramInterface (API)).

The performance of certain of the operations may be distributed amongthe processors, not only residing within a single machine, but deployedacross a number of machines. In some example embodiments, the processorsor processor-implemented modules are located in a single geographiclocation (e.g., within a home environment, an office environment, or aserver farm). In other example embodiments, the processors orprocessor-implemented modules are distributed across a number ofgeographic locations.

What is claimed is:
 1. A method comprising: operating an inertialmeasurement unit (IMU) in a first state of a plurality of states, thefirst state enabling the IMU to detect motion without determiningdirection of the motion; and in response to detecting motion,transitioning the IMU to a second state of the plurality of states, thesecond state enabling the IMU to detect directional information relatingto motion.
 2. The method of claim 1 further comprising: detecting afirst tap event while the IMU operates in the second state; and inresponse to detecting the first tap event, transitioning the IMU to athird state of the plurality of states, the third state storing a numberof acceleration measurements.
 3. The method of claim 2 wherein the firsttap event is detected by invoking a trained classifier to detect thefirst tap event based on acceleration data captured by the IMU.
 4. Themethod of claim 3, wherein invoking the trained classifier comprisescomparing filter responses to the acceleration data to filter responsesof training acceleration data.
 5. The method of claim 4, whereincomparing filter responses to the acceleration data to filter responsesof training acceleration data comprises comparing filter responses tothe acceleration data to filter responses of training acceleration dataindicating a touch event, and comparing the filter responses to theacceleration data to filter responses of training acceleration data thatdoes not indicate a touch event.
 6. The method of claim 4 wherein thepredetermined action is displaying, on an electronic display, a batterystatus indication.
 7. The method of claim 2 further comprising:detecting a third tap event while the IMU operates in the third state;and performing a predetermined action in response to detecting the thirdtap event.
 8. The method of claim 2 wherein the IMU consumes less powerwhen operating at the second state than at the third state.
 9. Themethod of claim 1 further comprising: changing a measurement rate of theIMU in response to an absence of touch events being detected over thethreshold amount of time.
 10. The method of claim 1 wherein the IMUconsumes less power when operating in the first state than the secondstate.
 11. The method of claim 1 wherein the IMU is part of a wearableelectronic device.
 12. The method of claim 1 wherein the IMU in thefirst state generates first accelerometer data at a first rate, the IMUin the second state generates second accelerometer data at a secondrate, and the second rate is greater than the first rate.
 13. Anelectronic device comprising: memory; and one or more processors coupledto the memory, the one or more processors configured to: operate aninertial measurement unit (IMU) in a first state of a plurality ofstates, the first state enabling the IMU to detect motion withoutdetermining direction of the motion; and in response to detectingmotion, transitioning the IMU to a second state of the plurality ofstates, the second state enabling the IMU to detect directionalinformation relating to motion.
 14. The electronic device of claim 13wherein the one or more processors are further configured to: detect afirst tap event while the IMU operates in the second state; and inresponse to detecting the first tap event, transitioning the IMU to athird state of the plurality of states, the third state storing a numberof acceleration measurements.
 15. The electronic device of claim 14wherein the first tap event is detected by invoking a trained classifierto detect the first tap event based on acceleration data captured by theIMU.
 16. The electronic device of claim 15, wherein invoking the trainedclassifier comprises comparing filter responses to the acceleration datato filter responses of training acceleration data.
 17. The electronicdevice of claim 16, wherein comparing filter responses to theacceleration data to filter responses of training acceleration datacomprises comparing filter responses to the acceleration data to filterresponses of training acceleration data indicating a touch event, andcomparing the filter responses to the acceleration data to filterresponses of training acceleration data that does not indicate a touchevent.
 18. The electronic device of claim 17 wherein the one or moreprocessors are further configured to: transition the IMU back to thesecond state when a second tap event is not detected after a thresholdamount of time while the IMU operates in the third state.
 19. Theelectronic device of claim 14 wherein the one or more processors arefurther configured to: detect a third tap event while the IMU operatesin the third state; and perform a predetermined action in response todetecting the third tap event.